when I get a new game, the first I need to know first is the storyline. If I don't know what the storyline is, I'm going to get lost. I'm like gonna say ' I don't get this storyline'. My first aspect is the storyline. That's my vote
For me its the storyline or the actual gameplay for the game if its a game i haven't played yet. then i probably look at the storyline..the graphics i notice right away but its not really a big aspect that i pay attention to. I would say last would be the BGM since i don't start to notice or pay attention to that until i'm more familiar with the storyline and gameplay of the game.
You left out the gameplay option. o.0 I think it's obvious what I look at first in a game. The puppi- *brick'd*. The gameplay! Story and characters are usually gameplay's second banana, music being the second banana to the second banana, and the graphics usually are the second banana to the second banana of the second banana.
Or in other words, it goes Gameplay, story/characters, music, graphics. Although that's not set in stone, sometimes the first thing I look at about a game is something other than the gameplay. It's usually the story in that case, but still.